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Perovskite solar cells suffer from instability primarily due to:
- Moisture sensitivity
- Thermal degradation
- Ion migration
- All of these
Answer: All of these
Hybrid perovskites (e.g., MAPbI₃) degrade under humidity, heat, light, electric fields. Research focuses on compositional engineering, encapsulation, inorganic perovskites for commercial viability. India's NISE supports R&D. [[MNRE Reports, NCERT Chemistry Class 12]]
Ion thrusters used in spacecraft propulsion accelerate ions using ________ fields to generate thrust.
- Magnetic
- Electric
- Gravitational
- Electromagnetic
Answer: Electric
Ion engines: electric fields accelerate xenon ions to high velocity, producing efficient low-thrust propulsion. Used in deep-space missions (e.g., Chandrayaan-2 orbiter). High specific impulse enables long-duration missions. [[ISRO Reports, NCERT Physics Class 11]]
Spatial transcriptomics combines gene expression profiling with ________ information to map RNA within tissue sections.
- Temporal
- Spatial
- Metabolic
- Proteomic
Answer: Spatial
Techniques like 10x Visium, MERFISH preserve tissue architecture while sequencing RNA. Reveals cell-cell interactions, tissue organization in development, disease. Transformative for cancer biology, neuroscience. [[DBT Reports, NCERT Biology Class 12]]
Strong gravitational lensing by massive galaxy clusters can produce:
- Einstein rings
- Multiple images of background sources
- Magnification of faint objects
- All of these
Answer: All of these
Massive objects bend spacetime, deflecting light from background sources. Strong lensing creates arcs, rings, multiple images; used to map dark matter, study early galaxies. ISRO's AstroSat contributes to multi-wavelength lensing studies. [[NCERT Physics Class 11, IUCAA Reports]]
The gut-brain axis involves communication via:
- Vagus nerve signaling
- Microbial metabolites (SCFAs)
- Immune system modulation
- All of these
Answer: All of these
Gut microbiota influence brain function and behavior through neural, endocrine, immune pathways. Links to depression, anxiety, neurodegenerative diseases. Probiotics/prebiotics being explored for mental health interventions. [[ICMR Reports, NCERT Biology Class 11]]
Metal-organic frameworks (MOFs) store hydrogen via ________ adsorption at cryogenic temperatures.
- Chemical
- Physical
- Electrochemical
- Biological
Answer: Physical
Physisorption: weak van der Waals forces bind H₂ to high-surface-area MOFs. Reversible, fast kinetics; challenges: low volumetric density at ambient conditions. Research focuses on optimizing pore chemistry for room-temperature storage. [[NCERT Chemistry Class 12]]
True or False: Small Modular Reactors (SMRs) offer enhanced safety features and flexibility compared to conventional large reactors.
- True
- False
Answer: True
SMRs (<300 MWe) use passive safety systems, factory fabrication, modular deployment. Suitable for remote areas, industrial heat, grid support. India's NPCIL is exploring SMR designs for domestic and export markets. [[DAE Reports, NCERT Physics Class 12]]
Green bonds are debt instruments issued to raise capital specifically for projects with ________ benefits.
- Social
- Environmental
- Economic
- Cultural
Answer: Environmental
Green bonds fund renewable energy, clean transport, sustainable water management, etc. India is among top emerging market issuers. SEBI's Green Bond Guidelines (2017) ensure transparency and impact reporting. [[SEBI, MoEFCC Reports]]
Electrochemical reduction of CO₂ can produce valuable chemicals like:
- Formic acid
- Carbon monoxide
- Ethylene
- All of these
Answer: All of these
CO₂ electrolysis using catalysts (Cu, Ag, molecular complexes) yields fuels/chemicals: CO, formate, ethylene, ethanol. Enables carbon recycling; challenges: selectivity, energy efficiency, scale-up. [[NCERT Chemistry Class 12, DST Reports]]
Quantum teleportation transfers the quantum state of a particle using ________ and classical communication.
- Entanglement
- Superposition
- Interference
- Diffraction
Answer: Entanglement
Quantum teleportation: entangled pair shared between sender/receiver; Bell measurement + classical bits enable state reconstruction. Does not transmit matter/energy; foundational for quantum internet. India's QuEST program advances this research. [[DST Reports]]
Which of the following is considered a potential climate tipping element?
- Amazon rainforest dieback
- West Antarctic Ice Sheet collapse
- Atlantic Meridional Overturning Circulation slowdown
- All of these
Answer: All of these
Tipping points: critical thresholds where small changes trigger large, irreversible shifts in Earth system. Monitoring these is crucial for climate risk assessment and policy. India's climate vulnerability increases with global tipping risks. [[MoES, MoEFCC Reports]]
Single-cell RNA sequencing (scRNA-seq) reveals ________ heterogeneity within tissues that bulk sequencing masks.
- Genetic
- Transcriptional
- Epigenetic
- Proteomic
Answer: Transcriptional
scRNA-seq profiles gene expression in individual cells, identifying rare cell types, developmental trajectories, disease subpopulations. Revolutionized immunology, neuroscience, cancer research. [[DBT Reports, NCERT Biology Class 12]]
Weyl semimetals host quasiparticles that behave like massless ________ fermions.
- Dirac
- Majorana
- Weyl
- Pauli
Answer: Weyl
Weyl fermions (predicted 1929, observed 2015) are chiral, massless excitations in topological semimetals. Exhibit exotic transport: chiral anomaly, Fermi arcs. Potential for low-power electronics, quantum computing. [[NCERT Physics Class 12, DST Reports]]
Federated learning trains AI models across decentralized devices while keeping data ________.
- Centralized
- Encrypted
- Local
- Anonymized
Answer: Local
Federated learning: model updates (not raw data) are shared from edge devices to central server. Preserves privacy, reduces bandwidth; used in healthcare (hospital data), mobile keyboards, IoT. Key for GDPR/DPDP-compliant AI. [[MeitY Reports]]
DNA methylation patterns at specific CpG sites can be used to estimate:
- Genetic ancestry
- Biological age
- Disease risk
- All of these
Answer: All of these
Epigenetic clocks (e.g., Horvath clock) predict biological age from methylation profiles. Accelerated aging correlates with disease, mortality. Applications: aging research, forensic age estimation, evaluating anti-aging interventions. [[ICMR Reports, NCERT Biology Class 12]]
Vanadium redox flow batteries store energy in liquid electrolytes containing ________ ions that undergo reversible redox reactions.
- Lithium
- Sodium
- Vanadium
- Zinc
Answer: Vanadium
VRFBs use V²⁺/V³⁺ (negative) and VO²⁺/VO₂⁺ (positive) couples in separate tanks. Power (stack size) and energy (tank volume) decoupled; ideal for grid-scale storage with long cycle life. [[MNRE Reports, NCERT Chemistry Class 12]]
True or False: Spintronics exploits the electron's spin degree of freedom, in addition to its charge, for information processing.
- True
- False
Answer: True
Spin-based devices (MRAM, spin transistors) offer non-volatility, lower power, higher speed vs. charge-only electronics. Applications: high-density storage, quantum computing interfaces. Emerging field in condensed matter physics. [[NCERT Physics Class 12]]
Explainable AI (XAI) techniques aim to make machine learning models:
- Faster
- More accurate
- Interpretable and transparent
- Smaller in size
Answer: Interpretable and transparent
XAI addresses 'black box' problem in complex models (deep learning) by providing human-understandable explanations for decisions. Critical for high-stakes domains: healthcare diagnostics, credit scoring, judicial support. [[NITI Aayog Principles for Responsible AI]]
True or False: The first synthetic bacterial cell (JCVI-syn1.0) was created by assembling a chemically synthesized genome and transplanting it into a recipient cell.
- True
- False
Answer: True
Venter Institute (2010) synthesized Mycoplasma mycoides genome (~1.08 Mbp), transplanted into M. capricolum, creating first self-replicating synthetic cell. Milestone in synthetic biology with biosecurity implications. [[DBT Reports, NCERT Biology Class 12]]
Enzyme immobilization on solid supports enhances catalyst reusability and stability for:
- Homogeneous catalysis
- Heterogeneous biocatalysis
- Photocatalysis
- Electrocatalysis
Answer: Heterogeneous biocatalysis
Immobilized enzymes combine biocatalyst specificity with heterogeneous catalyst recoverability. Used in pharmaceutical synthesis, biofuel production, biosensors. Aligns with green chemistry principles. [[NCERT Chemistry Class 12]]